Coated aeroplane cloth and process of making same



Patented Dec. 30,- 1924.

I 1,5 ,0 UNITEDSTATES'"PATENT oer-ice.

'rmaononn rnANgoIs :rnssn, or rams, nuance, AssreNon 'ro soomrnnao'ronnannies & DE mnsao, or s'r. oumr, rnancn, AND rmtononn rnanoorsmnssn,

or rams, amen.

COATED AEBDPLANE CLOTH AND PROCESS OF MAKING No Drawing. Applicationfiled October 4, 1916, Seriakgo. 123,640, I .Renewed v No. 428,815.

To all whom, it may concern:

Be it known that I, THEODORE FnANgoIs Tnssn, of 69 Avenue des Ternes,Paris, Republic of France, docteur es sciences, have invented a CoatedAeroplane Cloth and Process of Making Same, of which the following is afull, clear, and exact description.

This invention has for its object to provide 'an' improved process ofcoating aeroplane cloths, namely the cloths forming the surfaces of thewings of aeroplanes, by the employment of several layers each adapted toproduce certain desired efi'ects,vwhereby by the combination of suchlayers, the desirable effects of each are retained, and theseveralimpregnating solution, for whichpurpose a solution of celluloseacetate, in a volatile solvent is employed, and which solution does notnecessarily contain any. other ingredients. This solution is thenallowed to dry, that is to sav the solvent is allowed to evaporate, andin evaporating and drying, the effect of what is technically known asstretching is produced, that is'to say the fabric is put into what mightbe considered as a stretched condition, or in other words the fabric isput under considerable tension.

Step 2. The second step of the process consists in applying one or morelayers of a second coating, composed of a novel composition, coveredgenerically in my copendin'g application (filed Jan. 30, 1918, SerialNo. 214,525) whichcomposition may carry the pigment or color andingredients capable of modifying the effect of the first coating abovedescribed, and the third coating to be described below. The base of thissecond composition is a cellulose acetate solution (or other celluloseester solution) in a solvent of low boiling point, such as acetone-ormethyl acetate, together with a combination of vliquids of high boilingpoints, which liquids are capable of imparting plasticity and elasticityto the cellulose acetate.

Among su h q ids the foll wing are men- December a, 1320. Serial tionedz(a) the compounds of the'nfethyL. propylphenol series whos'e" boiling'points" are above 200C. and which are liquid at ordinary temperature,such as carvacrol, boiling point 236 C'., carvol, boiling point 225 C.,or (b) the others of -monatomic phenols, having unsaturated lateralchains and their isomers and their methylderivatives, and of this classeugenol (boiling point 247 C.) and iso-eugenol. (boiling point 260- C.)are bodies whi i have been found to be especially useful. hesesubstances nfay be used singly or in combina: tion, and there is alsopreferably added a substance capable of increasing the/supple: *ness andsoftness and flexibility, such as triacetin and also to this mixturethere is added a'body capable of preventing the precipitation ofcellulose ester, such as benzylic alcohol, or aceto-acetic ether. Tothis is also added an inert compound such.as pigment, for example zincoxid, the function of which is to counteract any excessive softnessproduced by the high boilingv point liquids in the large'quantity inwhich they are necessarily used. 1

In the resent invention, thereis also preferably a ded to this secondcoating composition, finely pulverized metal, such as aluminum, bronzeor copper, etc. Of these, aluminum is of particular importance, and thismetal is used in the form' of an impalpable powder.

The function of themetal is to strengthen the coating, to render thecoating more flexible, to still further reduce the inflammabilityof. thecoating, and also it has a particular effect on the visibility of theaeroplane.

The use of metallic powder allows of using a somewhat larger proportionof the hi h boilin oint li uids, without causin thg cloths ti li ecomeslack. g

To obtain a coating having suflicient elasticity, plasticity andsoftness, it has been found that relatively large quantities of highboiling point liquids are to be used and in such conditions the tensionof the cloth decreases in large proportion. For counteracting thisdetrimental efiect, an inert material is added in such pro ortions as torestore the strength of the coating and ing, and at the same-timemaintaining the necessarytension in the cloth.

The application of the coating composition to the planes has the etl'ectof metallizing them and by rcflectingthe light from the same, reducesthe visibility of the aeroplane, hence renders the determination andaltitude of the aeroplane (by observers lo- (ill eated on the ground ora distance away) much more difiicult. The metal particles act asreflectors for the rays of the sun, thereby prevents the sun frompenetrating into the coating, and hence prevents such decomposition ofthe components of the coating as are produced or accelerated by theaction of direct sunlight.

The following particulars are 'iven to illustrate a suitable method ofpreparing the improved coating composition for the second layer:

A solution of cellulose acetate in acetone or methyl acetate containing70 to 80 gms. of the cellulose ester per litre is prepared. 100 kgs. ofthis solution is mixed with 2 to 5 kgs. of pigment and preferably also 2to 3 kgs. of impalpable metallic powder (powdered aluminum, bronze,copper-or other metal); 2 kgs. of eugenol or other liquid having a highboiling point as stated above, 2 kgs, of benzylic alcohol, and 1 to 2kgs. of lriacetin are then added.

The proportions of these liquids of high boiling points should beincreased if it is desired to produce very flexible skins or coatings.

' After allowing this second coating to dry, it is pounced or rubbeddown very slightly, or is very lightly sand-papered.

This produces a dead flat surface.

Step 3. There is finally applied to the fabric treated as above, a thirdcoating, having the same or substantially the same composition as thefirst coating above referred to. By this application of a third coating,there is produc d the effect of imprisoning the second eoa ing, betweentwo closely adherent films of cellulose acetate.

Without limiting myself to the particular details given, and for thesake of illustration only, the following examples of the coatingcompositions are given. The first and third coating solutions may becomposed of about 8 parts by weight of cellulose acetate -'in 92 partsof aretone or methyl acetate.

' The second and intermediate coating composition may contain 8 parts byweight of cellulose acetate in 92 parts of acetone or methyl acetate, towhich there is added, per 100 kgs. of solution, 2 to 3 kgs. ofimpalpable metallic powder, such as aluminum, 2 to 5 kgs. of very fineand very light zinc oxid, and to 2 to 3 kgs. of eugenol, or one of theother high boiling point liquids added, together with 1 to 2 kgs. oftriacetin. There 1s also added aceto-acetic ether or benzylic alcohol,for facilitating the formation of a film. This mixture is thoroughlyground, for example in a paint mill.

In applying what is referred to as the second coating, in many cases itis advisable to apply several layers of the composition, and allow eachlayer to dry or partially dry, before adding the next layer.

The bottom layer, which impregnates the fabric, and also the top layer,both consisting (after the removal of solvent) essentially of celluloseacetate, are relatively rigid. These layers serve also to preventevaporation of the relatively non-volatile liquids mentioned, whichserve as plasticifying agents, agents imparting elasticity andsuppleness to the cellulose ester, which also carries the inertmaterial. The intermediatelayer is distinguished from the bottom and toplayers of the composite coating in that this intermediate layer ispermanently flexible, and hence modifies the effect of the rigid layers,and isitself in turn af fected thereby, so that the entire coating issimultaneously rigid and flexible.

It is to be understood that the improved ipetallic coating compositionis capable of eing poses andthat the proportions and nature of itsconstituents may be modified according to such purposes, and it is alsoto be understood that when metallic powders are employed as the inertsubstance, no chlorinated'products should be used as a solvent for thecellulose ether.

The process of the present application constitutes an improvement uponthat described and claimed in my copendin'g application 71,2()1, filedJan. 10, 1916, of which the present case is in part a continuation.

.I claim:

1. A process of coating fabrics, which comprises applying thereto insuccession,

used for numerous industrial purthree coatings, as follows :--first,' asolu- 1 tion in a volatile solvent containing a. cellulose ester as abase; second, a coating composition comprising a cellulose ester,liquids of high boiling point capable of imparting plasticity,elasticity and suppleness,

coating, whereby the second flexible coating is imprisoned between twolayers of more 'i rigid cellulose ester.

2..A process which comprises coating a fabric with a succession ofcoating layers, an intermediate one of said coating layers comprisin acellulose ester and a'plurality of normally non-volatile liquids capableof imparting plasticity, elasticity and supple- 1 ness, and capable ofpreventing the precipitation of the cellulose ester, and another liquidan intermediate one of said'coating layers comprising "a cellulose,ester and a plurality of normally non-volatile liquids capable ofimparting plasticity, elasticity and supple-' ness, and capable ofpreventing the precipitation of the cellulose ester,.and another liquidcapable of imparting softness and flexibility, and finely powderedaluminum, such intermediate layer being carried between two closelyadherent layers of less flexibility and of greater rigidity, whereby astructure is provided having a desired degree of rigidity andflexibility.

4. A fabric forming the covering of anaeroplane, said fabric beingprovided with a composite coating comprising a succession of at leastthree layers of compositions having afatty acid ester of cellulose as abase, an intermediate one of which layers has a greater elasticity andflexibility than the outer layers, and which contains a finely-dividedmetal.

5. A fabric having a composite coating comprising a succession of atleast three layersof material including acellulose ester of a fattyacid, an intermediate one of which layers containsmetal in the form ofan impalpable. powder and has as ingredients thereof, liquids of highboiling points including one which is capable bf imparting plasticityand elasticity, another which is capable of increasing the'suppleness.and softness and flexibility and another which is capable of preventingthe precipitation of the cellulose ester, the evaporation ofwhichliquids is prevented by the imprison ment of such layer between theouter layers.

6. A process of coating fabrics, which comprises applying thereto insuccession, three coatings, as follows :'.first, 'a solution in avolatile solvent containinga' cellulose ster as a base; second, acoating composition comprising a cellulose ester, liquids of high.boiling points, a volatile solvfiant for such 'constituents, and aninert .materi al- T and third, a solution in a volatile solvent:

ing each of the first two coatings to dry before applyin the nextcoating, whereby the second flexi le coating is imprisoned between twolayers of more rigid cellulose ester.

7. A process which comprises coating a fabric with a succession ofcoatings, ah in termediate one of said coatings comprising a celluloseester, a normally. non-volatile liquid capable of imparting plasticityand ing point not below 0., and capable of preventing precipitation ofthe cellulose ester, 'such intermediate layer being imprisoned betweenlayers of material substan-- tially impervious to such liquids.

8. A process which comprises first stretching the fabric on a frame, andthereafter coating such fabric with a succession of coatings, anintermediate one of said coatings comprising a cellulose ester of afatty acid, a normally non-volatile liquid capable of impartingplasticity and elasticity, and

another liquid capable of imparting softness and flexibility, suchintermediatelayer being carried between two closely adherent layers ofless flexibility and of greater rigidity, whereby a coated structureisprovided having a desired degree of rigidity and flexibility.

9. A fabric forming the covering of a wing of an aeroplane, said fabricbeing provided with a composite coating comprising a succession of atleast three layers of compositions each having a fatty acid ester ofcellulose as a base, an intermediate one of which layers has a greaterelasticity and flexibility than the outer layers, and which contains asolid. inert material.

10. A fabric provided with a composite pable of increasing theplasticity and elasticity of cellulose ester composition, another liquidcapable of increasing the suppleness and flexibility of cellulose estercomposition, and another liquid capable of preventing elasticity, andanother liquid having a boilprecipitation of cellulose ester in suchcomposition,-'the evaporation of which liquids .is' prevented by theimprisonment of suc layer be ween the outer layers.

11. A i rocess of impermeabilizing fabrics which comprises firstapplying thereto a solution of a cellulose ester, drying, then applyinga solution of a fatty acid ester of cellulose, in a volatile solvent,said solution containing as ingredients, non-volatile liq suppleness andsoftness and flexibility, and

.a. substance capableof preventing the preuids having highboiling'points including an plying a succession; of coating layers, the,j outer comprising a cellulose ester base, and "another comprisingcellulose ester With other cipitation of the cellulose ester during thecoating of a solution of cellulose fatty acid, and drying. 12. In thecoating. of

scribed improvement which comprises zapagent's capable; of preventing iprecipitation and of imparting plasticity, elasticity de- 'gree of:softness and suppleness; one of said i coating layers carrying:apigment.

' 13. The method of treating aeroplane. and- "Vsimilar-fabricseonsistingof applyinga com- "inga finish protectivecoating. I I

' i 14;.- 'The' method ofztreatingneroplane and I position comprisingeelluloseesteriin awola i I T tile solvent, applylnga'secondcompositioni e :comprisingcellulose esterandastabflmmg 1ingredient in a: volatilesolvanlg: and applysimilar fabrics consistingof applying a com- :1 position: comprising relatively non-inflame mablecellulose ester. and: applying to, $11011 stretching the fabric on" aframe: and there- I coated structure a separate: protective coat-C r mgcontammg; material} opaque, to act1n1orays I -15. A process whichcomprises first after coating such fabric with a succession of coatings,an intermediate one of said coatings comprising a cellulose ester of afatty tlie fabric formingthe coverings of an aeroplane, the herein.d'e-r acid. anda; normally, non-volatile liquid ca-c .pable of impartingplastieityand;elasticity,; V

such intermediatelayer being carried beof rigidity and flexibility 16: Afabric carried und 7 framework of; an, aeroplane element having upon,tl1e base of such coatinglayers being a cellulose :ester and anintermediate one of layers. v I I l i .17 f a framework; of an aeroplaneelement,- hav- .inga; plurality of dried coatinglayersthere-p I upon,the base of such coating layers being ers, and at least one of suchlayers carrying: a pigment as: aningredient I The =foregping specificaton of my coating;

intended more; particularly :for co'atingaero plane cloths, signed by methis 14th day. of. September, 1916.

tween two closely. adherent layers of less c flexibility and of greatrigidity, whereby; a I I I I whole is provided having a desired degree Ia plurality .ofdried coating layers :therei thes'aid layers iin'thei-rfinal dried state ha I 7 ing a greater degree of softness,= suppleness,I plasticity and; I elasticity, than the outer I a cellulose estelg; anintermediate one; of the said layers in theirfinal dried state having :agreater degree i026 softness, .suppleness, I plasticity and. elasticity:than the outer laye: I

e'r tension upon .a

fabric carried under tension upon eOmpositi-onand process of applyingsame, i c

' mnnononn'rnanoors rnssn.;. i

